Addition curable silicone adhesive compositions

ABSTRACT

A curable silicone adhesive composition comprising adhesion promoter is shown and described herein. The adhesion promoter is a silicon hydride material containing an aromatic based skeleton with another adhesion promoter to provide a silicone material that is curable at relatively low temperatures and shorter time and provides good adhesion to plastics and metal.

FIELD OF INVENTION

The present invention relates to curable silicone adhesive compositions, such compositions comprising adhesion promoters, and to the use and application of such curable silicone compositions on various surfaces. In particular, the present invention relates to a low temperature and fast curable silicone adhesive compositions comprising adhesion promoters and the application of such curable silicone compositions to different types of surfaces.

BACKGROUND

Plastics are replacing conventional materials for the development of next generation light-weight, efficient hybrid power modules, inverters, sensors, and electronic control unit (ECU) and transmission control unit (TCU) systems. Adhesives used in the automobile industry, for example, must be suitable to contribute to design flexibility and long term reliability under hard operating conditions. Conventional silicone compositions are generally not fully adhesive to plastic materials at lower temperatures. Plastic materials, however, are susceptible to deformation at higher processing temperatures (e.g., around 150° C.). Therefore, adhesive compositions that might require curing at elevated temperatures (e.g., greater than 120° C.) may not be particularly useful for certain applications and limit their use in various industries. Recent attempts to improve bonding of silicone to plastics have included the use of isocyanate based additives along with an aromatic group containing silicon hydride material (see, e.g., EP 2305765). Other attempts are described in, for example, U.S. Pat. Nos. 8,937,123 and 8,916,646, and Japan Publications 2014-205800 and 2013-241522. These proposed solutions, however, still require heating at temperatures in excess of 100° C.

SUMMARY

The following presents a summary of this disclosure to provide a basic understanding of some aspects. This summary is intended to neither identify key or critical elements nor define any limitations of embodiments or claims. Furthermore, this summary may provide a simplified overview of some aspects that may be described in greater detail in other portions of this disclosure.

Provided is an addition curable silicone adhesive composition which has been found to exhibit good adhesion to a variety of substrates, including both plastic substrates and metal substrates, and allow for curing of the composition at relatively low temperatures (e.g., about 100° C. or lower) and shorter time (e.g., about 30 to 60 min)

In one aspect, provided is a curable silicone composition comprising: (a) an alkenyl functional silicone; (b) a silicone based cross linker; (c) a filler; (d) a first adhesion promoter; (e) a second adhesion promoter; (f) optionally, a silane; (g) an inhibitor and (h) a catalyst, wherein the first adhesion promoter is chosen from a compound of the formula Z¹—R¹—O—Ar—O—R²—Z² where R¹ and R² are a C1-C30 divalent hydrocarbon; a C2-C20 divalent hydrocarbon; a C4-C10 divalent hydrocarbon; or a C1-C4 divalent hydrocarbon;

Z¹ and Z² are independently:

where R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are independently chosen from H, a C1-C10 alkyl, or —OR11, where R¹ is a C1-C10 alkyl, and at least one of R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and/or R¹⁰ are H;

X is 1 to 10; Y is 2 to 10; and

Ar is an aromatic group.

In one embodiment, the aromatic group Ar may be chosen from a C6-C30 arylene group, or a group of the formula —Ar¹—X—Ar²—, where Ar¹ and Ar² are independently chosen from a monocyclic divalent aryl group and X is a bridging group.

In one embodiment, Ar¹ and Ar² are independently chosen from a C6-C30 arylene group, X is chosen from a bond connecting Ar¹ and Ar², a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O)₂—, or —C(O)—.

In one embodiment, Ar¹—X—Ar² is a group of the formula:

where X is chosen from a bond connecting Ar¹ and Ar², a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O)₂—, or —C(O)—, R¹² and R¹³ are the same or different from each other or within the ring to which they are attached and are chosen from hydrogen, a C1-C10 alkyl, C1-C10 alkoxy, a C2-C8 alkenyl, a C2-C8 alkenyloxy, a C3-C8 cycloalkyl, a C3-C8 cycloalkoxy, a C6-C10 aryl, a C6-C10 aryloxy, a C7-C10 aralkoxy, a C7-C12 alkylaryl, or a C7-C12 alkylaryloxy, and t and w are 0-4, wherein when t or w are less than 4, the unspecified valence or valencies is occupied by hydrogen.

In one embodiment, —Ar¹—X—Ar² is of the formula:

where X is as described above, and R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰, and R²¹ are independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.

In one embodiment, X is —C(R²²)₂— where R₂₂ is independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.

In one embodiment, Z¹ and Z² are:

In one embodiment of the curable silicone composition of any previous embodiment, O—Ar—O of the compound is of the formula:

In one embodiment of the curable silicone composition of any previous embodiment, the first adhesion promoter is present in an amount of from about 0.1 wt. % to about 5 wt. % based on the total weight of the composition.

In one embodiment of the curable silicone composition of any previous embodiment, the second adhesion promoter is chosen from one or more compounds of the formula R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁷ is a hydrogen or hydride functional group; R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0, 1, or 2.

In one embodiment, R⁴⁷ is a cyclic hydrido siloxane containing group of the formula:

where R⁵¹, R⁵², and R⁵³ are independently chosen from H, a C1-C10 alkyl, or —OR⁵⁴, where R⁵⁴ is a C1-C10 alkyl, and at least one of R⁵¹, R⁵², and R⁵³ are H; and R⁵⁰ is an organosilicon group having a side chain bonded to a silicon atom and represented by the following formula

Q¹-C(O)—O-Q²

wherein: Q¹ represents a linear or branched alkylene group that forms a carbon chain having two or more carbon atoms between the silicon atom and an ester bond, and Q² represents a linear or branched alkylene group that forms a carbon chain having three or more carbon atoms between an oxygen atom and a silicon atom in a side chain: SiR⁴⁸ _(r)(OR⁴⁹)_(3-r).

In one embodiment, r is 0, and R⁴⁹ is a C1-C10 alkyl group.

In one embodiment of the curable silicone composition of any previous embodiment, the second adhesion promoter is present in an amount of from about 0.1 wt. % to about 10 wt. % based on the total weight of the composition.

In one embodiment of the curable silicone composition of any previous embodiment, the composition comprises second adhesion promoter (i) and (ii), wherein:

second adhesion promoter (i) is chosen from one or more compounds of the formula R⁴⁷SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁷ is a hydrogen or hydride functional group; R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0; and second adhesion promoter (ii) is chosen from a compound of the formula

R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0, 1, or 2, and R⁴⁷ is a cyclic hydrido siloxane containing group of the formula:

where R⁵¹, R⁵² and R⁵³ are independently chosen from H, a C1-C10 alkyl, or —OR⁵⁴, where R⁵⁴ is a C1-C10 alkyl, and at least one of and at least one of R⁵¹, R⁵², and R⁵³ are H; and R⁵⁰ is a C1-C30 hydrocarbon; a C6-C30 aryl group; a alkyl acrylate group; an alkyl carboxylate group; or an ester group.

In one embodiment, second adhesion promoter (i) is present in an amount of about 0.5 wt. % to about 3 wt. %, and second adhesion promoter (ii) is present in an amount of about 0.1 wt. % to about 8 wt. %.

In one embodiment of the curable silicone composition of any previous embodiment, the alkenyl silicone is chosen from a compound of the formula M¹ _(a)M² _(b)D² _(d)T¹ _(e)T² _(f)Q_(g) wherein:

-   -   M¹=R²³R²⁴R²⁵SiO_(1/2)     -   M²=R²⁶R²⁷R²⁸SiO_(1/2)     -   D¹=R²⁹R³⁰SiO_(2/2)     -   D²=R³¹R³²SiO_(2/2)     -   T²=R³³SiO_(3/2)     -   T²=R³⁴SiO_(3/2)     -   Q=SiO_(4/2)         where R²³, R²⁴, R²⁵, R²⁷, R²⁸, R²⁹, R³⁰, R³², and R³³ are         independently chosen from a C1-C30 hydrocarbon, a C6-C30         aromatic group, or C1-C30 alkoxy group;         R²⁶, R³¹, and R³⁴ are independently chosen from a C1-C30         hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a         C2-C30 alkenyl group, with the proviso that one or more of R²⁶,         R³¹, and/or R³⁴ are selected from a C2-C30 alkenyl group;         the subscripts a, b, c, d, e, f, g, are zero or positive subject         to the following limitations: 2<a+b+c+d+e+f+g<2000, b+d+f>0.

In one embodiment, the alkenyl silicone comprises a mixture of alkenyl silicones chosen from (i) a first alkenyl function silicone having the formula M²D¹ _(c)M² where c is from about 5 to about 1000; and a (ii) second alkenyl functional silicone having the formula M²D¹ _(c′)M² where c′ is from about 1000 to about 1500.

In one embodiment, the alkenyl silicone is a branched polyorganosiloxane comprising a plurality of Q_(g) units and one or more M² units.

In one embodiment of the curable silicone composition of any previous embodiment, the silicone hydride crosslinker is chosen from a compound of the formula:

M³ _(h)M⁴ _(i)D³ _(j)D⁴ _(k)T³ _(m)T⁴ _(n)Q_(o) wherein:

-   -   M³=R³⁵R³⁶R³⁷SiO_(1/2)     -   M⁴=R³⁸R³⁹R⁴⁰SiO_(1/2)     -   D³=R⁴¹R⁴²SiO_(2/2)     -   D⁴=R⁴³R⁴⁴SiO_(2/2)     -   T³=R⁴⁵SiO_(3/2)     -   T⁴=R⁴⁶SiO_(3/2)     -   Q=SiO_(4/2)         where R³⁵, R³⁶, R³⁷, R⁴¹, R⁴², R⁴⁵, and are independently chosen         from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30         alkoxy group;         R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and R⁴⁶ are independently chosen from         hydrogen, a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30         alkoxy group, or a C2-C30 alkenyl group, with the proviso that         one or more of R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and/or R⁴⁶ are hydrogen;         the subscripts a, b, c, d, e, f, g, are zero or positive subject         to the following limitations: 1<h+i+j+k+m+n+o<100, i+k+n>0.

In another aspect, provided is a cured silicone material formed from the composition of any of the previous embodiments.

In yet another aspect, provided is a method of forming an adhesive coating on a substrate comprising: applying a curable composition of any of the previous embodiments to a surface of a substrate, and heating the composition at a temperature of about 50° C. to about 110° C.

In one embodiment, the method comprises heating the composition at a temperature of about 60° C. to about 100° C.

In one embodiment of the method of any previous embodiment, the composition is cured over a period of 10 minutes to about 3 hours.

In one embodiment of the method of any previous embodiment, the substrate is chosen from a plastic material, metal, metal alloys, metallized plastic, and/or coated or painted metal.

The following description and the drawings disclose various illustrative aspects. Some improvements and novel aspects may be expressly identified, while others may be apparent from the description and drawings.

DETAILED DESCRIPTION

Reference will now be made to exemplary embodiments, examples of which are illustrated in the accompanying drawings. It is to be understood that other embodiments may be utilized and structural and functional changes may be made. Moreover, features of the various embodiments may be combined or altered. As such, the following description is presented by way of illustration only and should not limit in any way the various alternatives and modifications that may be made to the illustrated embodiments. In this disclosure, numerous specific details provide a thorough understanding of the subject disclosure. It should be understood that aspects of this disclosure may be practiced with other embodiments not necessarily including all aspects described herein, etc.

As used herein, the words “example” and “exemplary” means an instance, or illustration. The words “example” or “exemplary” do not indicate a key or preferred aspect or embodiment. The word “or” is intended to be inclusive rather than exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g., A employs B; A employs C; or A employs both B and C). As another matter, the articles “a” and “an” are generally intended to mean “one or more” unless context suggest otherwise.

Provided is an addition curable silicone adhesive composition comprising silicon based adhesion promoters. The silicon based adhesion promoters have an aromatic skeleton with silicon containing groups attached to the aromatic backbone and at least one hydrogen bonded to a silicon atom. The silicone based adhesion promoters may be derived from dihydroxy aromatic compounds. The present silicone based adhesion promoters function to improve the adhesion of siloxane based curable compositions to a substrate such as those formed from or having a plastic surface. When used in conjunction with other adhesion promoters, the present silicone based adhesion promoters may provide curable silicone compositions that exhibit good adhesion on a metal such as aluminum as well as different types of plastic surfaces (e.g., PBT and PPS), while curing at low temperatures (about 100° C. or lower) and shorter time (30 to 60 min).

In one aspect, provided is a silicone based material that is suitable to function as an adhesion promoter in a curable composition. The silicone based material is an aromatic silicon hydride type material. The silicone based adhesion promoter contains an aromatic group and is derived from a dihydroxy aromatic compound. In one embodiment, the silicone based adhesion promoter is a compound of the formula:

Z¹—R¹—O—Ar—O—R²—Z²

where R¹ and R² are a C1-C30 divalent hydrocarbon; a C2-C20 divalent hydrocarbon; a C4-C10 divalent hydrocarbon; or a C1-C4 divalent hydrocarbon; Z¹ and Z² are independently:

where R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are independently chosen from H, a C1-C10 alkyl, or —OR11, where R¹¹ is a C1-C10 alkyl, and at least one of R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and/or R¹⁰ are H;

X is 1 to 10; Y is 2 to 10; and

Ar is an aromatic group.

The aromatic group Ar may be chosen from a C6-C30 arylene group, or a group of the formula —Ar¹—X—Ar²—, where Ar¹ and Ar² are independently chosen from a monocyclic divalent aryl group and X is a bridging group. Ar¹ and Ar² may be independently chosen from a C6-C30 arylene group. X may be a bond connecting Ar¹ and Ar², a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O)₂—, —C(O)—. Non-limiting examples of suitable bridging groups X include methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecylidene, cyclododecylidene, and adamantylidene.

In one embodiment, Ar¹—X—Ar² is a group of the formula:

where X is as described above, R² and R¹³ are the same or different from each other or within the ring to which they are attached and are chosen from hydrogen, a C1-C10 alkyl, C1-C10 alkoxy, a C2-C8 alkenyl, a C2-C8 alkenyloxy, a C3-C8 cycloalkyl, a C3-C8 cycloalkoxy, a C6-C10 aryl, a C6-C10 aryloxy, a C7-C10 aralkoxy, a C7-C12 alkylaryl, or a C7-C12 alkylaryloxy, and t and w are 0-4, wherein when t or w are less than 4, the unspecified valence or valencies is occupied by hydrogen.

In one embodiment, —Ar¹—X—Ar² is of the formula:

where X is as described above, and R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰, and R²¹ are independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl. In one embodiment, X is —C(R²²)₂— where R₂ is independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl. In one embodiment, the —O—Ar—O— portion of the compound is of the formula:

The silicone based adhesion promoters may be derived from dihydroxy aromatic compounds. The dihydroxy aromatic compounds may be of the formula HO—Ar—OH, where Ar is as described above. For the sake of brevity, the description of the Ar groups is not reproduced. Some illustrative, non-limiting examples of suitable dihydroxy aromatic compounds to form the adhesion promoters include, but are not limited to, the following: 4,4′-dihydroxybiphenyl, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxy-3 methyl phenyl)cyclohexane 1,1-bis(4-hydroxyphenyl)isobutene, 1,1-bis(4-hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4-hydroxyphenyl)adamantine, (alpha,alpha′-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene, 4,4′-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone, 1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorine, 2,7-dihydroxypyrene, 6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindane bisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine, 3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole, and the like, resorcinol, substituted resorcinol compounds such as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromo resorcinol, or the like; catechol; hydroquinone; substituted hydroquinones such as 2-methyl hydroquinone, 2-ethyl hydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone, 2,3,5,6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluoro hydroquinone, 2,3,5,6-tetrabromo hydroquinone, as well as combinations comprising at least one of the foregoing dihydroxy aromatic compounds.

The present silicone based adhesion promoters may be formed by any suitable method. In embodiments, the silicone based adhesion promoter is formed by reacting the dihydroxy aromatic compound (HO—Ar—OH) with an alkenyl halide to a compound with a formula of the formula R^(1′)—O—Ar—O—R^(2′) where R^(1′) and R^(2′) are each an alkenyl terminal hydrocarbon, and then reacting that compound with a hydrido siloxane via a hydrosilylation type reaction. Any suitable hydrosilylation catalyst (e.g., platinum based catalysts like Karstedt's or Ashby's catalysts, or others) may be used to promote the reaction of the alkenyl containing compounds with the hydrido siloxanes.

The present silicone based adhesion promoters are suitable for use in a variety of applications. In one aspect, the present silicone based adhesion promoters have been found to be particularly useful in curable silicone compositions and particularly, have been found to be useful to provide a low temperature curable silicone composition. The use of the present silicone based adhesion promoters have been found to provide good adhesion to a variety of surfaces including both metals and different types of plastics at relatively low temperatures (e.g., 100° C. or lower).

In one aspect, provided is a curable silicone composition comprising: (a) an alkenyl functional silicone; (b) a silicone based cross linker; (c) a filler; (d) a first adhesion promoter chosen from the present silicone based adhesion promoters; (e) a second adhesion promoter; (f) optionally, a silane; (g) an inhibitor and (h) a catalyst. The combination of the present silicone based adhesion promoters with the second adhesion promoter have been found to provide good adhesion to a broad range of surfaces and curing at relatively low temperatures.

The alkenyl functional silicone can be an organopolysiloxane having one or more alkenyl groups bonded to a silicon atom. In one embodiment, the composition includes an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms. The composition may include a mixture of two or more different alkenyl functional silicone compounds.

In one embodiment, the composition includes an alkenyl functional silicone compound of the formula:

M¹ _(a)M² _(b)D¹ _(c)D² _(d)T¹ _(e)T² _(f)Q_(g)

wherein:

-   -   M¹=R²³R²⁴R²⁵SiO_(1/2)     -   M²=R²⁶R²⁷R²⁸SiO_(1/2)     -   D¹=R²⁹R³⁰SiO_(2/2)     -   D²=R³¹R³²SiO_(2/2)     -   T¹=R³³SiO_(3/2)     -   T²=R³⁴SiO_(3/2)     -   Q=SiO_(4/2)

where R²³, R²⁴, R²⁵, R²⁷, R²⁸, R²⁹, R³⁰, R³², and R³³ are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;

R²⁶, R³¹, and R³⁴ are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R²⁶, R³¹, and/or R³⁴ are selected from a C2-C30 alkenyl group;

the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 2<a+b+c+d+e+f+g<2000, b+d+f>0.

In one embodiment, the alkenyl functional silicone comprises two or more alkenyl functional groups (i.e., b+d+f>2). In one embodiment, the alkenyl functional silicone is of the formula M²D¹ _(e)M².

Further, it will be appreciated that the composition can include a mixture of two or more alkenyl functional silicones. Where a plurality of alkenyl functional silicones are used, the alkenyl functional silicones may be of different types (e.g., have a different overall makeup in terms of the M, D, T, and Q units), or of different sizes (e.g., have similar M, D, T, Q structures but differ in terms of the number of a particular unit). In one embodiment, the composition comprises a first alkenyl function silicone having the formula M²D¹ _(c)M² where c is from about 5 to about 1000; and a second alkenyl functional silicone having the formula M²D¹ _(c′)M² where c′ is from about 1000 to about 1500.

In one embodiment, the alkenyl functional silicone is a branched, cage-like oligosiloxane containing one or more alkenyl groups bonded to silicon atoms. The branched alkenyl functional silicone includes Q units (SiO_(4/2) units), M units (R₃SiO_(1/2) units), and optionally further including D units (R₂SiO units) and/or T units (R₃SiO_(3/2) units) (wherein R is each independently an unsubstituted or substituted monovalent aliphatic group or alicyclic group), wherein at least three of R's per molecule are preferably alkenyl groups. It will be appreciated that such branched, cage-like siloxanes are encompassed by the alkenyl functional siloxane compound described by formula M¹ _(a)M² _(b)D¹D² _(d)T¹ _(e)T² _(f)Q_(g)

The alkenyl functional silicone (or mixture of two or more alkenyl functional silicones) is present in an amount of from about 40 to about 75 weight %; from about 45 to about 65 weigh %; or from about 52 to about 58 weight % based on the total weight of the composition.

The composition includes an organohydrogendpolysiloxane. The organohydrogendpolysiloxane may be chosen from a compound of the formula:

M³ _(h)M⁴ _(i)D³ _(j)D⁴ _(k)T³ _(m)T⁴ _(n)Q_(o)

wherein:

-   -   M³=R³⁵R³⁶R³⁷SiO_(1/2)     -   M⁴=R³⁸R³⁹R⁴⁰SiO_(1/2)     -   D³=R⁴¹R⁴²SiO_(2/2)     -   D⁴=R⁴³R⁴⁴SiO_(2/2)     -   T³=R⁴⁵SiO_(3/2)     -   T⁴=R⁴⁶SiO_(3/2)     -   Q=SiO_(4/2)

where R³⁵, R³⁶, R³⁷, R⁴¹, R⁴², R⁴⁵, and are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;

R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and R⁴⁶ are independently chosen from hydrogen, a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and/or R⁴⁶ are hydrogen;

the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 1<h+i+j+k+m+n+o<100, i+k+n>0.

The hydride functional silicone crosslinker (or mixture of two or more alkenyl functional silicones) is present in an amount of from about 0.01 to about 20 weight %; from about 0.1 to about 5 weight %; or from about 0.1 to about 2 weight % based on the total weight of the composition.

The filler (c) useful in the present invention is a filler or mixture of fillers that is selected from those that are now known or later found to be useful in silicone compositions, provided they do not significantly impair the translucency of the coating, i.e., that a substrate coated maintains its original appearance following application of the coating thereof.

Examples of suitable fillers (c) include, but are not limited to, ground, precipitated and colloidal calcium carbonates which are treated with compounds such as stearate or stearic acid; reinforcing silicas such as fumed silicas, precipitated silicas, silica gels and hydrophobized silicas and silica gels; crushed and ground quartz, alumina, aluminum hydroxide, titanium hydroxide, diatomaceous earth, iron oxide, carbon black, graphite or clays such as kaolin, bentonite, or montmorillonite.

In one embodiment, the filler (c) is a silica filler, such as a silica filler treated with a D4 and hexamethyldisilazane or a combination thereof. The amount of filler useful in the present invention is generally from about 1 weight % to about 50 weight %, more preferably from about 5 weight % to about 30 weight %, and most preferably from about 8 weight % to about 20 weight % based on the total weight of the curable silicone composition.

The curable composition includes a first adhesion promoter (d) chosen from an aromatic silicone based adhesion promoter as previously described herein. For the sake of brevity, the details of the aromatic silicone based adhesion promoter is not reproduced. The aromatic silicone based adhesion promoter may be provided in an amount of from about 0.1% to about 5%; from about 0.5% to about 3%; or from about 0.5% to about 2% by weight based on the total weight of the composition.

The curable composition optionally includes a second adhesion promoter chosen from a hydride functional alkoxy silane. In one embodiment, the hydride functional alkoxy silane is chosen from a compound of the formula:

R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r)

where R⁴⁷ is a hydrogen or hydride functional group; R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r=0, 1, or 2.

Examples of substituent R⁴⁸ and R⁴⁹ groups include, but are not limited to, alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, octyl, and decyl; alkenyl groups such as 2-propenyl, hexenyl, and octenyl; aralkyl groups such as benzyl and phenethyl; aryl groups such as phenyl, tolyl, and xylyl.

Specific examples of the hydrido (hydrocarbonoxy)silane include trialkoxysilanes, trialkenoxysilanes, and triaryloxysilanes. Examples of trialkoxysilanes include trimethoxysilane, triethoxysilane, tri-n-propoxysilane, triisopropoxysilane, tributoxysilane, triisopropenoxysilane, and triphenoxysilane. Examples of dialkoxysilanes, dialkenoxysilanes, and diaryloxysilanes include methyldimethoxysilane, methyldiethoxysilane, methyldi-n-propoxysilane, methydiisopropenoxysilane, methyldiphenoxysilane, ethyldimethoxysilane, ethyldiethoxysilane, n-propyldimethoxysilane, n-propyldiethoxysilane, 3,3,3-trifluoropropyldimethoxysilane, 3,3,3-trifluoropropyldiethoxysilane, n-hexyldimethoxysilane, n-hexyldiethoxysilane, n-octyldimethoxysilane, n-octyldiethoxysilane, benzyldimethoxysilane, benzyldiethoxysilane, phenethyldimethoxysilane, phenethyldiethoxysilane, phenyldimethoxysilane, and phenyldiethoxysilane. Examples of monoalkoxysilanes, monoalkenoxysilanes, and monoaryloxysilanes include dimethylmethoxysilane, dimethylethoxysilane, dimethyl-n-propoxysilane, dimethylisopropenoxysilane, dimethylphenoxysilane, diethylmethoxysilane, methylethylethoxysilane, n-propyl(methyl)methoxysilane, n-propyl(methyl)ethoxysilane, 3,3,3-trifluoropropyl(methyl)methoxysilane, bis (3,3,3-trifluoropropyl)ethoxysilane, n-hexyl(methyl)methoxysilane, di(n-hexyl)ethoxysilane, n-octyl (methyl)methoxysilane, di(n-octyl)ethoxysilane, benzyl(methyl)methoxysilane, phenethyl(methyl) methoxysilane, and methylphenylmethoxysilane. Examples of hydrido (hydrocarbonoxy)silanes with mixed alkoxy groups, alkenoxy groups, aralkyloxy groups, and aryloxy groups include diethoxypropenoxysilane, dimethoxyphenoxysilane, diphenoxypropenoxysilane, and methylmethoxyphenethoxysilane.

In embodiments, R⁴⁷ is a cyclic hydrido siloxane containing group of the formula:

where R⁵¹, R⁵², and R⁵³ are independently chosen from H, a C1-C10 alkyl, or —OR⁵⁴, where R⁵⁴ is a C1-C10 alkyl, and at least one of R⁵¹, R⁵², and R⁵³ are H; and R⁵⁰ is a C1-C30 hydrocarbon; a C6-C30 aryl group; an alkyl acrylate group; an alkyl carboxylate group; or an ester group. In one embodiment, the hydride functional alkoxy silane of the formula R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r), R⁴⁷ is a cyclic hydrido siloxane, R⁵⁰ is a C1-C30 hydrocarbon; a C6-C30 aryl group; an alkyl acrylate group; an alkyl carboxylate group; or an ester group, and r is 0 such that the compound includes a trialkoxysilyl group. In one embodiment, R⁵⁰ is an organosilicon group having a side chain bonded to a silicon atom and represented by the following formula

Q¹-C(O)—O-Q²

wherein: Q¹ represents a linear or branched alkylene group that forms a carbon chain having two or more carbon atoms between the silicon atom and an ester bond, in embodiments 2-20 carbon atoms, 4-15 carbon atoms, or 6-10 carbon atoms, and Q² represents a linear or branched alkylene group that forms a carbon chain having three or more carbon atoms between an oxygen atom and a silicon atom in embodiments 2-20 carbon atoms, 4-15 carbon atoms, or 6-10 carbon atoms, in a side chain: SiR⁴⁸ _(r)(OR⁴⁹)_(3-r).

Various organofunctional silane and siloxane adhesion promoters to inorganic substrates are useful in the composition as the second adhesion promoter. Suitable silanes include, but are not limited to, epoxy silanes, isocyanurate silanes, imido silanes, anhydride silanes, carboxylate functionalized siloxanes, etc. Combinations of various types of adhesions promoters may also be used. Such components typically hinder curing via metal catalyzed hydrosilylation. Suitable adhesion promoters include, but are not limited to various aminosilane materials such as Silquest® A-1120 silane, Silquest A-1110 silane, Silquest A-2120 silane, and Silquest A-1170 silane; epoxysilanes, such as Silquest A-187 silane; isocyanurate silanes such as Silquest A-597 silane; and mercaptosilanes such as Silquest A-189 silane, Silquest A-1891 silane, Silquest A-599 silane available from Momentive Performance Materials.

The second adhesion promoter may be present in an amount of about 0.1% to about 10%; from about 0.2% to about 5%; or from about 0.5% to about 3% by weight based on the total weight of the composition. In embodiment employing the second adhesion promoter, the ratio of the first adhesion promoter to the second adhesion promoter may be from about 3:5; about 3:1; or from about 1:1.

The curable composition optionally further includes an alkoxy silane (f). The alkoxy silane (f) is a compound of the formula:

R⁵⁵—SiR⁵⁶ _(n)(OR⁵⁷)_(3-n)

where R⁵⁵, R⁵⁶, and R⁵⁷ are independently chosen from a C1-C30 hydrocarbon, and/or a C6-C30 aromatic group, and R⁵⁵ is chosen from a C1-C30 hydrocarbon, a C6-30 aromatic group, a C1-C30 alkoxy group, or a C2-C20 unsaturated hydrocarbon.

Examples of suitable alkoxy silanes (f) include, but are not limited to, tetramethoxy silane, tetraethoxy silane, tetra-n-propoxy silane, methoxy triethoxy silane, dimethoxy diethoxy silane, trimethoxy-n-propoxy silane, bis(2-ethylhexoxy)diethoxy silane, methyl trimethoxy silane, methyl triethoxy silane, amyl triethoxy silane, triethoxy silane, methyl triacetoxy silane, phenyl trimethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, allyl trimethoxy silane, allyl triethoxy silane, gamma-aminopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane, beta-aminoethyl trimethoxy silane, beta-aminoethyl triethoxy silane, N-beta-aminoethylaminopropyl trimethoxy silane, gamma-isocyanatopropyl triethoxy silane, mercaptopropyl trimethoxy silane, mercaptoethyl trimethoxy silane, mercaptopropyl triethoxy silane, glycidoxypropyl trimethoxy silane, glycidoxypropyl triethoxy silane, 4,5-epoxycyclohexylethyl trimethoxy silane, ureidopropyl trimethoxy silane, ureidopropyl triethoxy silane, chloropropyl trimethoxy silane, chloropropyl triethoxy silane, cyanopropyl trimethoxy silane, etc.

It will be appreciated that two or more different alkoxy silanes may be employed as the alkoxy silane (f). The alkoxy silane, when present, may be present in an amount of about 0.1% to about 5%; from about 0.1% to about 3%; or from about 0.1% to about 2.5% by weight based on the total weight of the composition.

The curable composition optionally includes a polymerization inhibitor (g). The polymerization inhibitor is not particularly limited and may be chosen as desired for a particular purpose or intended use. Examples of suitable inhibitors include, but are not limited to, ethylenically unsaturated amides, aromatically unsaturated amides, acetylenic compounds, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon diesters, unsaturated hydrocarbon mono-esters of unsaturated acids, conjugated or isolated ene-ynes, hydroperoxides, ketones, sulfoxides, amine, phosphines, phosphites, nitrites, diaziridines, etc. Particularly suitable inhibitors for the compositions are alkynyl alcohols and maleates. Examples of suitable polymerization inhibitors include, but are not limited to, diallyl maleate, hydroquinone, p-methoxyphenol, t-butylcatechol, phenothiazine, etc.

The amount of inhibitor (g) to be used in the compositions is not critical and can be any amount that will retard the above reaction at room temperature while not preventing said reaction at moderately elevated temperature, i.e. a temperature that is 75 to 100° C. The range of component (g) can be 0 to about 10% weight, about 0.001 to 2% by weight, even about 0.12 to about 1 by weight. Here as elsewhere in the specification and claims, numerical values can be combined to form new and alternative ranges.

The hydrosilylation catalyst (h) can include precious metal catalysts such as, but not limited to, those which use ruthenium, rhodium, palladium, osmium, iridium, and platinum, and complexes of these metals. Examples of suitable hydrosilylation catalysts for use in the present invention include, but are not limited to: Ashby catalysts; Lamoreax catalysts; Karstedt catalysts; Modic catalysts; and Jeram catalysts and combinations of two or more thereof.

In one embodiment, the compositions can be free of any inhibitor component (g) and Pt catalyst (h).

The curable composition may also comprise other additives (i). Other additives may include, but are not limited to, an antioxidant, a filler, pigments, dyes, filler treating agent, plasticizer, spacer, extender, biocide, stabilizer, flame retardant, surface modifier, anti-aging additive, rheological additive, corrosion inhibitor, surfactant or combination thereof.

The curable compositions may also include an antioxidant compound. Examples of suitable classes of antioxidant compounds include, but are not limited to, hindered amines and/or hindered phenol compounds.

Examples of hindered amine antioxidant compounds include, but are not limited to Hindered amine series antioxidant (N,N′,N″,N′″-tetrakis-(4,6-bis(butyl-(N-methy)-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazine-2-yl)-4,7-diazadecan-1,10-diamine, a polycondensation product of dibutylamine-1,3,5-triazine-N,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine-N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol, [a reaction product of decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidyl) ester, 1,1-dimethylethylhydroperoxide and octane] (70%)-polypropylene (30%), bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9, 9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione, etc.).

In one embodiment, the antioxidant compound is a hindered phenolic compound. The hindered phenol can be chosen as desired for a particular purpose or intended application. Examples of suitable hindered phenols include, but are not limited to, monophenols such as 2,6-di-t-butyl-p-cresol, 2-t-butyl-4-methoxyphenol, 3-t-butyl-4-methoxyphenol, and 2,6-t-butyl-4-ethylphenol, bisphenols such as 2,2′-methylene-bis(4-methyl-6-t-butylphenol), 4,4′-thiobis(3-methyl-6-t-butylphenol), and 4,4′-butylidene-bis(3-methyl-6-t-butylphenol); and polymeric phenols such as 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tri s(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane, bis[3,3′-bis(4′-hydroxy-3-t-butylphenyl)butyric acid glycol ester, and tocopherol (vitamin E), pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene-bis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), N,N′-hexane-1,6-diylbis [3-(3,5-di-tert-butyl-4-hydroxyphenylpropioamide), benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy C7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3′,3″,5,5′,5″-hexane-tert-butyl-4-a,a′,a″-(mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethylbis[[[3,5-bis-(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate], 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, a reaction product of N-phenylbenzeneamine and 2,4,4-trimethylpentene, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-ylamino)phenol etc.).

IRGANOX 1330 is a sterically hindered phenolic antioxidant (“3,3′,3′,5,5′,5′-hexa-tert-butyl-a,a′,a′-(mesitylene-2,4,6-triyl)tri-p-cresol”) commercially available from BASF. Irganox 1010 is a sterically hindered phenolic antioxidant (“Pentaerythritol Tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)”) commercially available from BASF, or 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene commercially available as ETHANOX™ 330 (Albemarle Corporation), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (Irganox 3114), tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate as Irganox 3114.

The curable composition may optionally comprise a photostabilizer. The photostabilizer is not particularly limited and may be chosen as desired for a particular application or intended use. Examples of suitable materials for the photstabilizer include, but are not limited to, 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, a reaction product of methyl 3-(3-(21-1-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate/polyethylene glycol 300, 2-(2H-benzotriazol-2-yl)-6-(straight and branched dodecyl)-4-methylphenol, 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol, octabenzone, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, tinuvin 622LD, Tinuvin 144, CHIMASSORB 119FL, MARK LA-57, LA-62, LA-67, LA-63, SANDOL LS-765, LS-292, LS-2626, LS-1114, LS-744, etc.

The curable compositions may be cured by providing a mixture of the respective components and exposing the mixture to a sufficient temperature for a sufficient time to cure the composition. The respective components may be added separately or as two or more packages of materials where a package includes two or more of the components required for the final composition. In one embodiment, the adhesion promoters are provided as a package including (i) the aromatic based silicone compounds as the first adhesion promoter and (ii) a second adhesion promoter. In one embodiment, the composition may be heated at a temperature below 150° C.; below 125° C.; below 110° C.; below 100° C.; or below 90° C. In one embodiment, the composition is heated at a temperature of from about 75° C. to about 120° C.; from about 85° C. to about 110° C.; or from about 90° C. to about 100° C. Curing may be accomplished under exposure to an elevated temperature for a period of from about 10 minutes to about 3 hours; 15 minutes to about 1.5 hours; or about 30 minutes to about 1 hour.

The compositions may be used in a variety of applications. In embodiments, the compositions may be cured and used as materials for sealing, as adhesives; as coatings in sanitary rooms; as joint seal between different materials, e.g., sealants between ceramic or mineral surfaces and thermoplastics; as paper release; as impregnation materials; weather strip coatings, release coatings, adhesives, adhesion finishes, leak tight products, pointing products, foams, etc. As examples, the compositions can be cured and used as a general purpose and industrial sealant, potting compound, caulk, or adhesive for construction use, insulated glass, where glass sheets are fixed and sealed in metal frame; caulks, adhesives for metal plates, car bodies, vehicles, electronic devices, and the like.

Further, the compositions may be employed on a variety of substrates and provide excellent adhesive properties. Examples of suitable substrates include, polymeric substrates that may include, but are not limited to, organic polymeric materials such thermoplastic resin selected from acrylonitrile-butadiene-styrene (ABS) resin, polycarbonate (PC) resin, polyurethane (PU) resin, styrene resin, polyethylene (PE) resin, polypropylene (PP) resin, acrylic resin, polyethylene terephthalate (PET) resin, polybuthylene terephthalate (PBT) resin, polyphenylene oxide (PPO) resin, polyphenylene sulfide (PPS) resin, polysulfone resin, nylon (PA) resin, aromatic polyamide (aromatic PA) resin, polyimide (PI) resin, and liquid crystal resin. The compositions also can be used to adhere to metal substrates including aluminum, iron, nickel, stainless steel, metal alloys and plated metal.

The following examples are intended to illustrate aspects and embodiments of the present technology. All parts and percentages are by weight and all temperatures are in Celsius unless explicitly stated otherwise. All patents, other publications, and U.S. patent applications referred to in the instant application are incorporated herein by reference in their entireties.

Examples

Compositions were prepared according to the examples listed in Tables 1 and 2. The compositions were prepared by adding the adhesion promoter(s) to the compositions and mixing to disperse into the composition. The hydride alkoxy silane adhesion promoter Silane A is a silane falling under R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁷ is a cyclic hydrido siloxane having a group Q¹-C(O)—O-Q² attached thereto as described in the specification. The compositions were applied to a surface of an aluminum substrate, a polyphenylene sulfide (PPS) substrate, or a polybutylene terephthalate (PBT) substrate within a Teflon groove having dimensions of 145 mm²×0.15 mm deep. The substrates were placed in an oven and cured at 90-100° C. for 30-60 min. Lap shear strength of the cured material was measured using an INSTRON 3365 tensile strength tester a test method ASTM D 3163.

TABLE 1 1 2 3 4 5 Vinyl Polymer A-1 M^(Vi)D₁₁₀₀M^(Vi) 45 45.69 45.14 45.69 30.98 A-2 M^(Vi)D₅₆₀M^(Vi) 10 10.15 10.03 10.15 B-1 M₆D^(Vi)Q₈ 5 5.08 5.02 5.08 21.69 Si-H Cross E-1 MD^(H) ₂₃D₁₆M 1.5 1.52 1.20 1.52 1.49 Linker Filler C-1 HMDZ treated Fumed Silica 10 10.15 10.03 10.15 18.59 (200 m³/g) C-2 Quartz Filler 25 25.38 25.08 25.38 24.78 Hydride alkoxy D-1 Silane A 2 0.51 2.01 0.51 0.00 silane-AP D-2 Silane B—Triethoxysilane (TES) — 1.24 BPA-AP D-5 BPA Derivative 1.5 1.52 1.50 1.52 1.24 (organosiliocn containing at least one phenylene skeleton) Alkoxy silane- D-3 Tetraethyl Silicate (TEOS) 2 2 2 2 AP D-4 Vinyl triethoxy Silane (VTES) 0.2 Inhibitor F-1 Diallyl Maleate 0.1 0.1 0.1 0.1 0.25 Hardness 22 25 20 24 38 A1 Lap shear strength, MPa 2.5 2.9 2.3 2.9 4.8 Cohesion failure % 100% 100% 100% 100% 100% PBT Lap shear strength, MPa 2.2 2.5 2.0 2.4 4.2 Cohesion failure % 100% 100% 100% 100% 100% PPS Lap shear strength, MPa 2.0 2.4 2.0 2.2 3.5 Cohesion failure % 100% 100% 100% 100% 100%

TABLE 2 6 7 8 9 10 11 Vinyl Polymer A-1 M^(Vi)D₁₁₀₀M^(Vi) 45.69 46.63 45.82 45.69 45.92 49.18 A-2 M^(Vi)D₅₆₀M^(Vi) 10.15 10.36 10.18 10.15 10.20 10.93 B-1 M₆D^(Vi)Q₈ 5.08 5.18 5.09 5.08 5.10 0.00 Si-H Cross E-1 MD^(H) ₂₃D₁₆M 1.52 1.55 1.22 1.52 1.53 1.64 Linker Filler C-1 HMDZ treated 10.15 10.36 10.18 10.15 10.20 10.93 Fumed Silica (200 m³/g) C-2 Quartz Filler 25.38 25.91 25.46 25.38 25.51 27.32 Hydride alkoxy D-1 Silane A 2.03 2.04 2.03 silane-AP D-2 Silane B— Triethoxysilane (TES) BPA-AP D-5 BPA Derivative 1.53 (organosiliocn containing at least one phenylene skeleton) Alkoxy silane- D-3 Tetraethyl 2 2 2 1 1 1 AP Silicate (TEOS) D-4 Vinyl triethoxy 0.2 0.2 0.2 Silane (VTES) Inhibitor F-1 Diallyl Maleate 0.1 0.1 0.1 0.1 0.1 0.1 Hardness 22 26 20 21 25 22 Al Lap shear 2.5 3.0 2.3 2.3 3.1 2.3 strength, MPa Cohesion failure 100% 100% 100% 100% 100% 100% % PBT Lap shear 2.0 0.5 1.8 1.9 2.5 1.7 strength, MPa Cohesion failure 100%  0% 100% 100% 100%  0% % PPS Lap shear 1.3 0.2 1.5 1.3 1.5 0.5 strength, MPa Cohesion failure 30% 0% 50% 30% 50% 0% %

Examples 6-9 and 11 may be seen as comparative examples. As illustrated in the tables, the present adhesion promoters provide good adhesion compared to the use of other adhesion promoters alone. (See Table 2.) Additionally, the use of the present adhesion promoters in conjunction with a second adhesion promoter also provides improved adhesion and across a broader spectrum of substrates.

What has been described above includes examples of the present specification. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present specification, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present specification are possible. Accordingly, the present specification is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

The foregoing description identifies various, non-limiting embodiments of a aromatic-containing silicone compound and curable compositions comprising such compounds. Modifications may occur to those skilled in the art and to those who may make and use the invention. The disclosed embodiments are merely for illustrative purposes and not intended to limit the scope of the invention or the subject matter set forth in the claims. 

1. A curable silicone composition comprising: (a) an alkenyl functional silicone; (b) a silicone based cross linker; (c) a filler; (d) a first adhesion promoter; (e) a second adhesion promoter; (f) optionally, a silane; (g) an inhibitor and (h) a catalyst, wherein the first adhesion promoter is chosen from a compound of the formula Z¹—R¹—O—Ar—O—R²—Z² where R¹ and R² are a C1-C30 divalent hydrocarbon; a C2-C20 divalent hydrocarbon; a C4-C10 divalent hydrocarbon; or a C1-C4 divalent hydrocarbon; Z¹ and Z² are independently:

where R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are independently chosen from H, a C1-C10 alkyl, or —OR11, where R¹¹ is a C1-C10 alkyl, and at least one of R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and/or R¹⁰ are H; X is 1 to 10; Y is 2 to 10; and Ar is an aromatic group.
 2. The curable silicone composition of claim 1, wherein the aromatic group Ar may be chosen from a C6-C30 arylene group, or a group of the formula —Ar¹—X—Ar²—, where Ar¹ and Ar² are independently chosen from a monocyclic divalent aryl group and X is a bridging group.
 3. The curable silicone composition of claim 2, wherein Ar¹ and Ar² are independently chosen from a C6-C30 arylene group, X is chosen from a bond connecting Ar¹ and Ar², a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O)₂—, or —C(O)—.
 4. The curable silicone composition of claim 2, wherein Ar¹—X—Ar² is a group of the formula:

where X is chosen from a bond connecting Ar¹ and Ar², a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O)₂—, or —C(O)—, R¹² and R¹³ are the same or different from each other or within the ring to which they are attached and are chosen from hydrogen, a C1-C10 alkyl, C1-C10 alkoxy, a C2-C8 alkenyl, a C2-C8 alkenyloxy, a C3-C8 cycloalkyl, a C3-C8 cycloalkoxy, a C6-C10 aryl, a C6-C10 aryloxy, a C7-C10 aralkoxy, a C7-C12 alkylaryl, or a C7-C12 alkylaryloxy, and t and w are 0-4, wherein when t or w are less than 4, the unspecified valence or valencies is occupied by hydrogen.
 5. The curable silicone composition of claim 2, wherein —Ar¹—X—Ar² is of the formula:

where X is as described above, and R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰, and R²¹ are independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.
 6. The curable silicone composition of claim 5, wherein X is —C(R²²)₂— where R₂₂ is independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.
 7. The silicone compound of claim 6, wherein Z¹ and Z² are:


8. The curable silicone composition of claim 1, wherein the O—Ar—O of the compound is of the formula:


9. The curable silicone composition of claim 1, wherein the first adhesion promoter is present in an amount of from about 0.1 wt. % to about 5 wt. % based on the total weight of the composition.
 10. The curable composition of claim 1, wherein the second adhesion promoter is chosen from one or more compounds of the formula R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁷ is a hydrogen or hydride functional group; R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0, 1, or
 2. 11. The curable composition of claim 10, wherein R⁴⁷ is a cyclic hydrido siloxane containing group of the formula:

where R⁵¹, R⁵², and R⁵³ are independently chosen from H, a C1-C10 alkyl, or —OR⁵⁴, where R⁵⁴ is a C1-C10 alkyl, and at least one of R⁵¹, R⁵², and R⁵³ are H; and R⁵⁰ is an organosilicon group having a side chain bonded to a silicon atom and represented by the following formula Q¹-C(O)—O-Q² wherein: Q¹ represents a linear or branched alkylene group that forms a carbon chain having two or more carbon atoms between the silicon atom and an ester bond, and Q² represents a linear or branched alkylene group that forms a carbon chain having three or more carbon atoms between an oxygen atom and a silicon atom in a side chain: SiR⁴⁸ _(r)(OR⁴⁹)_(3-r).
 12. The curable composition of claim 11, wherein r is 0, and R⁴⁹ is a C1-C10 alkyl group.
 13. The curable composition of claim 1, wherein the second adhesion promoter is present in an amount of from about 0.1 wt. % to about 10 wt. % based on the total weight of the composition.
 14. The curable composition of claim 1 comprising second adhesion promoter (i) and (ii), wherein: second adhesion promoter (i) is chosen from one or more compounds of the formula R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁷ is a hydrogen or hydride functional group; R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0; and second adhesion promoter (ii) is chosen from a compound of the formula R⁴⁷—SiR⁴⁸ _(r)(OR⁴⁹)_(3-r) where R⁴⁸ is independently selected from a C1-C10 hydrocarbon group; each R⁴⁹ is independently selected from a C1-C10 hydrocarbon; and r is 0, 1, or 2, and R⁴⁷ is a cyclic hydrido siloxane containing group of the formula:

where R⁵¹, R⁵², and R⁵³ are independently chosen from H, a C1-C10 alkyl, or —OR⁵⁴, where R⁵⁴ is a C1-C10 alkyl, and at least one of and at least one of R⁵¹, R⁵², and R⁵³ are H; and R⁵⁰ is a C1-C30 hydrocarbon; a C6-C30 aryl group; a alkyl acrylate group; an alkyl carboxylate group; or an ester group.
 15. The curable silicone composition of claim 14, wherein second adhesion promoter (i) is present in an amount of about 0.5 wt. % to about 3 wt. %, and second adhesion promoter (ii) is present in an amount of about 0.1 wt. % to about 8 wt. %.
 16. The curable silicone composition of claim 1, wherein the alkenyl silicone is chosen from a compound of the formula M¹ _(a)M² _(b)D¹ _(c)D² _(d)T¹ _(e)T² _(f)Q_(g) wherein: M¹=R²³R²⁴R²⁵SiO_(1/2) M²=R²⁶R²⁷R²⁸SiO_(1/2) D¹=R²⁹R³⁰SiO_(2/2) D²=R³¹R³²SiO_(2/2) T¹=R³³SiO_(3/2) T²=R³⁴SiO_(3/2) Q=SiO_(4/2) where R²³, R²⁴, R²⁵, R²⁷, R²⁸, R²⁹, R³⁰, R³², and R³³ are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group; R²⁶, R³¹, and R³⁴ are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R²⁶, R³¹, and/or R³⁴ are selected from a C2-C30 alkenyl group; the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 2<a+b+c+d+e+f+g<2000, b+d+f>0.
 17. The curable silicone composition of claim 16, wherein the alkenyl silicone comprises a mixture of alkenyl silicones chosen from (i) a first alkenyl function silicone having the formula M²D¹ _(e)M² where c is from about 5 to about 1000; and a (ii) second alkenyl functional silicone having the formula M²D¹ _(c′)M² where c′ is from about 1000 to about
 1500. 18. The curable composition of claim 1, wherein the alkenyl silicone is a branched polyorganosiloxane comprising a plurality of Q_(g) units and one or more M² units.
 19. The curable silicone composition of claim 1, wherein the silicone hydride crosslinker is chosen from a compound of the formula: M³ _(h)M⁴ _(i)D³ _(j)D⁴ _(k)T³ _(m)T⁴ _(n)Q_(o) wherein: M³=R³⁵R³⁶R³⁷SiO_(1/2) M⁴=R³⁸R³⁹R⁴⁰SiO_(1/2) D³=R⁴¹R⁴²SiO_(2/2) D⁴=R⁴³R⁴⁴SiO_(2/2) T³=R⁴⁵SiO_(3/2) T⁴=R⁴⁶SiO_(3/2) Q=SiO_(4/2) where R³⁵, R³⁶, R³⁷, R⁴¹, R⁴², R⁴⁵, and are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group; R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and R⁴⁶ are independently chosen from hydrogen, a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R³⁸, R³⁹, R⁴⁰, R⁴³, R⁴⁴, and/or R⁴⁶ are hydrogen; the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 1<h+i+j+k+m+n+o<100, i+k+n>0.
 20. A cured silicone material formed from the composition of claim
 1. 21. A method of forming an adhesive coating on a substrate comprising: applying a curable composition of claim 1 to a surface of a substrate, and heating the composition at a temperature of about 50° C. to about 110° C.
 22. The method of claim 21 comprising heating the composition at a temperature of about 60° C. to about 100° C.
 23. The method of claim 21, wherein the composition is cured over a period of 10 minutes to about 3 hours.
 24. The method of claim 21, wherein the substrate is chosen from a plastic material, metal, metal alloys, metallized plastic, and/or coated or painted metal. 